Deexcitation and three-body ionic recombination of atomic nitrogen by heavy species impact

This work compares several theories for deexcitation and three-body ionic recombination of atomic nitrogen by heavy-species impact. First, we present an extensive comparison of all available experimental and theoretical state-specific data and identify a general trend. Second, we retain the best candidates and incorporate them successively into a collisional-radiative model. In each case, we compute the effective rate coefficient for three-body ionic recombination N⁺ + e⁻ + M → N + M. This allows us to compare their global behavior in the depletion of ionic species and to test whether they are consistent with the diffusive approximation in the low-temperature regime (T<2000 K), which serves as a reference. Third, we test all the models by simulating a nitrogen-argon comparison experiment for which the electronic distribution is non-Boltzmann and sensitive to the choice of the heavy-species impact deexcitation theory. This three-step study concludes with a recommendation of the best models.